Scientists discover way to authenticate purity of cacao beans

January 17th, 2014

In the American Chemical Society’s Journal of Agricultural and Food Chemistry, scientists from the US Government’s Sustainable Perennial Crops Laboratory report a method to authenticate the varietal purity and origin of cacao beans, the source of chocolate’s main ingredient, cocoa.

Dapeng Zhang and colleagues note that lower-quality cacao beans often get mixed in with premium varieties on their way to becoming chocolate bars, truffles, sauces and liqueurs – potentially deceiving consumers. There’s also a conservation angle to knowing whether products are truly what confectioners claim them to be, the researchers note, as the ability to authenticate premium and rare varieties would encourage growers to maintain cacao biodiversity rather than depend on the most abundant and easiest to grow trees.

Researchers have found ways to verify through genetic testing the authenticity of many other crops, including cereals, fruits, olives, tea and coffee, but those methods aren’t suitable for cacao beans. Zhang’s team wanted to address this challenge.

Applying the most recent developments in cacao genomics, they were able to identify a small set of DNA markers called SNPs that make up unique fingerprints of different cacao species. The technique works on single cacao beans and can be scaled up to handle large samples quickly.

“To our knowledge, this is the first authentication study in cacao using molecular markers,” the researchers said.